1. Measurement of Dijet Cross-Sections at Low $Q^{2}$ and the Extraction of an Effective Parton Density for the Virtual Photon
- Author
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Adloff, C., Andreev, V., Andrieu, B., Arkadov, V., Astvatsatourov, A., Ayyaz, I., Babaev, A., Bahr, J., Baranov, P., Barrelet, E., Bartel, W., Bassler, U., Bate, P., Beglarian, A., Behnke, O., Behrend, H.J., Beier, C., Belousov, A., Berger, C., Bernardi, G., Berndt, T., Bertrand-Coremans, G., Biddulph, P., Bizot, J.C., Boudry, V., Braunschweig, W., Brisson, V., Brown, D.P., Bruckner, W., Bruel, Pascal, Bruncko, D., Burger, J., Busser, F.W., Buniatian, A., Burke, S., Burrage, A., Buschhorn, G., Calvet, D., Campbell, A.J., Carli, T., Chabert, E., Charlet, M., Chyla, J., Clarke, D., Clerbaux, B., Contreras, J.G., Cormack, C., Coughlan, J.A., Cousinou, M.C., Cox, B.E., Cozzika, G., Cvach, J., Dainton, J.B., Dau, W.D., Daum, K., David, M., Davidsson, M., De Roeck, A., De Wolf, E.A., Delcourt, B., Demirchian, R., Diaconu, C., Dirkmann, M., Dixon, P., Dlugosz, W., Donovan, K.T., Dowell, J.D., Droutskoi, A., Ebert, J., Eckerlin, G., Eckstein, D., Efremenko, V., Egli, S., Eichler, R., Eisele, F., Eisenhandler, E., Elsen, E., Enzenberger, M., Erdmann, M., Fahr, A.B., Faulkner, P.J.W., Favart, L., Fedotov, A., Felst, R., Feltesse, J., Ferencei, J., Ferrarotto, F., Fleischer, M., Flugge, G., Fomenko, A., Formanek, J., Foster, J.M., Franke, G., Gabathuler, E., Gabathuler, K., Gaede, F., Garvey, J., Gassner, J., Gayler, J., Gerhards, R., Ghazaryan, S., Glazov, A., Goerlich, L., Gogitidze, N., Goldberg, M., Gorelov, I., Grab, C., Grassler, H., Greenshaw, T., Griffiths, R.K., Grindhammer, G., Hadig, T., Haidt, D., Hajduk, L., Hampel, M., Haustein, V., Haynes, W.J., Heinemann, B., Heinzelmann, G., Henderson, R.C.W., Hengstmann, S., Henschel, H., Heremans, R., Herynek, I., Hewitt, K., Hiller, K.H., Hilton, C.D., Hladky, J., Hoffmann, D., Horisberger, R., Hurling, S., Ibbotson, M., Issever, C., Jacquet, M., Jaffre, M., Janauschek, L., Jansen, D.M., Jonsson, L., Johnson, D.P., Jones, M., Jung, H., Kastli, H.K., Kander, M., Kant, D., Kapichine, M., Karlsson, M., Karschnik, O., Katzy, J., Kaufmann, O., Kausch, M., Keller, N., Kenyon, I.R., Kermiche, S., Keuker, C., Kiesling, C., Klein, M., Kleinwort, C., Knies, G., Kohne, J.H., Kolanoski, H., Kolya, S.D., Korbel, V., Kostka, P., Kotelnikov, S.K., Kramerkamper, T., Krasny, M.W., Krehbiel, H., Krucker, D., Kruger, K., Kupper, A., Kuster, H., Kuhlen, M., Kurca, T., Lachnit, W., Lahmann, R., Lamb, D., Landon, M.P.J., Lange, W., Langenegger, U., Lebedev, A., Lehner, F., Lemaitre, V., Lemrani, R., Lendermann, V., Levonian, S., Lindstroem, M., Lobo, G., Lobodzinska, E., Lubimov, V., Luders, S., Luke, D., Lytkin, L., Magnussen, N., Mahlke-Kruger, H., Malden, N., Malinovskii, E., Malinovski, I., Maracek, R., Marage, P., Marks, J., Marshall, R., Martyn, H.U., Martyniak, J., Maxfield, S.J., McMahon, T.R., Mehta, A., Meier, K., Merkel, P., Metlica, F., Meyer, A., Meyer, H., Meyer, J., Meyer, P.O., Mikocki, S., Milstead, D., Mohr, R., Mohrdieck, S., Mondragon, M., Moreau, F., Morozov, A., Morris, J.V., Muller, D., Muller, K., Murin, P., Nagovizin, V., Naroska, B., Naumann, J., Naumann, T., Negri, I., Newman, P.R., Nguyen, H.K., Nicholls, T.C., Niebergall, F., Niebuhr, C., Niedzballa, C., Niggli, H., Nix, O., Nowak, G., Nunnemann, T., Oberlack, H., Olsson, J.E., Ozerov, D., Palmen, P., Panassik, V., Pascaud, C., Passaggio, S., Patel, G.D., Pawletta, H., Perez, Emile, Phillips, J.P., Pieuchot, A., Pitzl, D., Poschl, R., Pope, G., Povh, B., Rabbertz, K., Rauschenberger, J., Reimer, P., Reisert, B., Reyna, D., Rick, H., Riess, S., Rizvi, E., Robmann, P., Roosen, R., Rosenbauer, K., Rostovtsev, A., Rouse, F., Royon, C., Rusakov, S., Rybicki, K., Sankey, D.P.C., Schacht, P., Scheins, J., Schilling, F.P., Schleif, S., Schleper, P., Schmidt, D., Schoeffel, L., Schroder, V., Schultz-Coulon, H.C., Sefkow, F., Semenov, A., Shekelian, V., Shevyakov, I., Shtarkov, L.N., Siegmon, G., Sirois, Y., Sloan, T., Smirnov, P., Smith, M., Solochenko, V., Solovev, Yu., Spaskov, V., Specka, A., Spitzer, H., Squinabol, F., Stamen, R., Steffen, P., Steinberg, R., Steinhart, J., Stella, B., Stellberger, A., Stiewe, J., Straumann, U., Struczinski, W., Sutton, J.P., Swart, M., Tapprogge, S., Tasevsky, M., Chernyshov, V., Chechelnitskii, S., Theissen, J., Thompson, G., Thompson, P.D., Tobien, N., Todenhagen, R., Traynor, D., Truol, P., Tsipolitis, G., Turnau, J., Tzamariudaki, E., Udluft, S., Usik, A., Valkar, S., Valkarova, A., Vallee, C., Van Esch, P., Van Haecke, A., Van Mechelen, P., Vazdik, Ya., Villet, G., Wacker, K., Wallny, R., Walter, T., Waugh, B., Weber, G., Weber, M., Wegener, D., Wegner, A., Wengler, T., Werner, M., West, L.R., White, G., Wiesand, S., Wilksen, T., Willard, S., Winde, M., Winter, G.G., Wissing, C., Wittek, C., Wittmann, E., Wobisch, M., Wollatz, H., Wunsch, E., Zacek, J., Zalesak, J., Zhang, Zhiqing, Zhokin, A., Zini, P., Zomer, F., Zsembery, J., Zur Nedden, M., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), H1, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
High Energy Physics - Experiment (hep-ex) ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,FOS: Physical sciences ,High Energy Physics::Experiment ,High Energy Physics - Experiment - Abstract
The triple-differential dijet cross-section, d^3 sigma_{ep}/dQ2 dE_t2 dxgjets, is measured with the H1 detector at HERA as a function of the photon virtuality Q^2, the fraction of the photon's momentum carried by the parton entering the hard scattering, xgjets, and the square of the mean transverse energy, E_t2, of the two highest E_t jets. Jets are found using a longitudinal boost-invariant k_T clustering algorithm in the gamma* p center of mass frame. The measurements cover the ranges 1.6 < Q^2 < 80 GeV$^2 in virtuality and 0.1 < y < 0.7 in inelasticity y. The results are well described by leading order QCD models which include the effects of a resolved component to the virtual photon. Models which treat the photon as point-like fail to describe the data. An effective leading order parton density for the virtual photon is extracted as a function of the photon virtuality, the probing scale and the parton momentum fraction. The x_gamma and probing scale dependences of the parton density show characteristic features of photon structure, and a suppression of this structure with increasing Q^2 is seen., 32 pages, 10 figures, 4 tables, submitted to Eur. Phys. J. C
- Published
- 2000